Actually, if wikipedia is to be believed, Silver Surfer is right:
The rest of the telephone monopoly lasted until final settlement of a 1974 United States Department of Justice antitrust suit against AT&T on January 8, 1982, under which AT&T ("Ma Bell") agreed to divest its local exchange service operating companies, in return for a chance to go into the computer business (see AT&T Computer Systems). AT&T's local operations were split into seven independent Regional Bell Operating Companies known as "Baby Bells".
Note: Bold mine.
So the US government did
disassemble AT&T. Unless Wikipedia is wrong (which it could be)...then it needs some editin'...